The acoustic mode of operation is the native mode of operation of a wind musical instrument. In this mode, the sound is produced by vibrations of the air column of the instrument which are triggered by the blowing of the player.
A digital mode of operation consists in equipping a wind musical instrument with electronic components which make it possible to produce digital sounds obtained by a sound synthesis technique applied to one or more electrical signals produced by the components.
The digital mode of operation of a wind musical instrument in particular makes it possible to make the instrument silent by playing back the digitized sound to the player through a headset. In effect, acoustic musical practice can be a source of sound nuisance and can constrain a musician to play only during certain time periods, or even discourage him or her from practicing this instrument.
Another advantage of digital operation is the widening of the range of tones by virtue of a sound synthesis technique.
One problem to be solved in this context is how to design an electronic system that can be combined with the acoustic wind instrument which can easily be reversible for the user to be able to switch from a digital mode of operation to an acoustic mode of operation.
Another problem to be solved is how to design a system which makes it possible to perform a sound synthesis from interactions of the musician with the instrument.
A first approach for rendering an instrument silent consists in attenuating the sound produced by the instrument. Methods for that are known that are based on the use of absorbent materials of foam type or methods based on attenuation by wrapping. These methods are non-intrusive and inexpensive but they are not sufficiently effective over all of the acoustic spectrum considered. Generally, the sound produced by the wind instruments with lateral holes is more difficult to attenuate than the sound produced by other instruments, for example the instruments from the brass family.
Another approach for limiting the sound nuisances consists in using a device that replaces the acoustic operation of the instrument, in other words a totally digital instrument. This type of instrument simultaneously makes it possible to measure blowing parameters (intensity and pinching of the lips) as well as the position of the fingers on the instrument. The keys can be static or mechanical. Coupled with a synthesizer, this type of instrument makes it possible to have a wide range of tones and proves easy to use. Its minimalist technical design makes it a product that is relatively approachable in terms of costs. On the other hand, the control of such a device is different from a clarinet or a saxophone because of the configuration and the mechanical behavior of the keys and of the mouthpiece. This instrument therefore requires a complementary and an unshared learning which is unsatisfactory when the musician wants to increase his or her competence with his or her acoustic instrument.
The European patent publications EP1585107 and EP2017823 and the American patent publication U.S. Pat. No. 7,501,570 describe hybrid wind instruments which alternatively allow acoustic or digital operation. The digitization techniques considered in these patents are based on Hall-effect sensors or on infrared detectors which have to be positioned on each key of the instrument permanently and in separately. These techniques therefore require a significant number of sensors which are not reversible and which can disturb the operation of the instrument in acoustic mode.
The present invention proposes an electronic system that can be combined with a wind musical instrument with lateral holes which is based on the detection of the state of closing of the holes of the instrument via emitters and receivers of ultrasound acoustic signals or, more generally, of elastic mechanical waves.